“Probably one of the most unfortunate things in a ‘Bloke’s Life’ is that it takes over 30 years to realise how essential you have been to build my character, my ethics and, most importantly, my HAPPINESS,” it reads.

“At 32, I am finally starting to figure it out. In good times and in bad, you were there.

“Your strength and endurance to raise me will not go unrewarded. My love for you is my strength!

Tertius Pickard/AP
Bob Irwin with Slash, who once paid a visit to the zoo

“For the rest of my life I will reflect on the unbelievably GREAT times we’ve shared and will continue to share. You’re my best friends!”

Steve’s parents were also naturalists, and inspired their sons love for all things outdoors.

Since his death, his family have continued with the work he did in Australia, running the 100-acre Australia Zoo that he pioneered.